Method and an implement arrangement for the removal of fasteners in the form of rings

ABSTRACT

A method and an implement for the removal of rings (3) from material (1) such as canvas. The ring exhibits a flange-like side part (7, 9) to either side of the material, which side parts are attached to a tubular part (8) which extends through a hole (2) in the material. Removal is effected by the ring (3) being pressed between two parts (4, 5) of an implement, one (4) of which parts is forced against one side of the ring adjacent to its inner edge (16), and the other (b 5) is forced against the other side adjacent to the outer edge (20) of the ring. In this way a radial distance is provided between the engaging edges of both implements, and the ring is subjected to a tilting moment which, when the parts of the implement are pressed together, produces the conical form which causes it to be released from the material.

TECHNICAL FIELD

In conjunction with sails and other canvas materials use is made offasteners in the form of rings which afford protection to holes made inthe canvas. In line with the increasing strength of the canvas materialimparted by new fibres and manufacturing processes, it has beennecessary to adapt the rings to suit the higher stresses which areimposed on the canvas. In order to achieve increased strength in thering and to improve its holding properties, rings have been producedfrom very strong material and with a toothed engagement in the canvas. Aring of this kind is disclosed in British Pat. No. 2 123 337,Rutgersson.

Technical Problem

The rings are permanently installed as a general rule, although incertain cases it is necessary to make changes or to carry out repairs ofa kind which require one or more of the rings to be removed. The removalof the rings is made more difficult by the increased strength of therings and their improved holding properties. Removal is madeparticularly difficult and is associated with a considerable risk ofdamage to the canvas in the case of those rings which, like the ring inaccordance with the indicated patent, are equipped with tags whichpenetrate through the canvas and are also curved at their tips. Theremoval of such rings generally requires the outer parts of the rings tobe parted, for example by grinding, and for the teeth to be bent out, inthe event of these being bent around the canvas, one by one so that theycan be withdrawn together with that part of the ring to which they areattached.

The object of the present invention is to make available a method forthe removal of rings, in particular those which are used in sails andother canvas materials which are of the heavy-duty type, executed inaccordance with what is stated in this patent, for example. Theinvention also relates to an implement arrangement which can be used forthe execution of the method.

The Solution

Removal is effected by the ring being pressed between two implementparts, one of which implement parts is forced against one side of thering along a line which is concentric with the tubular part on its edge,and the other part of the implement on the other side of the ring isforced along a line which follows the ring on its outer edge. A radialdistance is thus provided between the engaging edges of both implements,in this way subjecting the ring to a tilting movement, viewed over itscross-section, which, when the parts of the implement are pressedtogether, produces the conical form with a progressively reducing angleuntil that side part against which the first part of the implement is inengagement assumes an at least near enough cylindrical appearance, inwhich case said ring-shaped part of the ring can be released throughbeing enabled to pass over the last-mentioned, compressed side partwhilst the ring-shaped part is likewise caused to adopt a concial form.The arrangement comprises the two parts of the implement for theaforementioned engagement circumstances.

Advantages

What is achieved through the invention is that rings, including those ofthe heavy-duty kind and those which are equipped with teeth, can beremoved without the canvas being damaged and in such a way that theteeth can be withdrawn from the canvas without ripping it.

Removal can be executed in accordance with the method and with the helpof the implement arrangement as a single operation in a force-applyingarrangement such as a press. Such force-applying arrangements are usedby all those who are involved with the fitting of rings of theaforementioned heavy-duty type. Removal can thus largely be executedusing existing equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

The method in accordance with the invention is illustrated stage bystage in the accompanying drawyings, from which the implementarrangement can also be appreciated.

FIGS. 1-3 illustrate different stages in the removal operation, from thesecurely installed ring in a state in which it has not yet beenprocessed ready for removal, to the fully released ring.

All the Figures present a central cross-section through the ring and thesurrounding part of a piece of canvas in which it is fitted, togetherwith parts of the implement arrangement, which latter is also presentedas a central cross-section.

BEST MODE OF CARRYING OUT THE INVENTION

The designation 1 is used in the Figures in respect of a canvas with acircular hole 2 and a ring 3 fitted around the area of the canvassurrounding the hole. The implement arrangement is also shown in theFigure as a mandrel 4 and a support 5 in tubular form.

FIG. 1 shows the ring 3 in a securely installed state before it has yetbeen subjected to the removal operation. In this state the ring exhibitsa circular main component 6 made of a metal such as stainless steel. Themain component 6 exhibits a first, flangelike side part 7 which istransformed into a tubular part 8, which is in turn transformed into asecond side part 9 on the opposite side of the canvas in relation to theposition of the side part 7. The tubular part 8 has its diameter adaptedto suit the hole 2 through the canvas 1. The side part 9 has beenproduced by imparting outward curvature to the tubular part 8, which, inthe manufactured state of the main component 6, is fully cylindrical andalso includes the material which now forms the side part 9.

The ring 3 also incorporates adjacent to the side part 9 a ring 11 withteeth 12 positioned in a circular row and made of a metal such asstainless steel. Adjacent to the side part 7 is a further ring 13 madeof plastic.

In conjunction with the installation of the ring 3, the aforementionedcylindrical part, of which the part 8 constitutes a part, is pushedthrough the hole 2 in the canvas 1 after the plastic ring 13 has firstbeen placed against the side part 7. The ring 11 with the teeth 12 isthen positioned, which teeth face straight towards the canvas in thisposition. Considerable force is then applied so as to cause thecylindrical part to curve outwards to form the flange-like side part 9,in conjunction with which the teeth 12 are forced through the canvas 1and penetrate through the plastic ring 13 and are bent in the mannerillustrated in FIG. 1 against the side part 7, which is discshaped forthis purpose. The ring is now securely retained, partly by the holdingaction in the canvas of the teeth 12 arranged in the form of a ring, forwhich purpose the teeth are supported by the plastic ring 13, and partlyby the clamping of the canvas which is produced through the pressure ofthe ring 11 and the plastic ring 13 exerted by the side parts 7 and 9which are curved in towards one another.

The parts of the implement have their dimensions adapted to suit thediameter of a ring which is to be removed. The mandrel 4 mustaccordingly exhibit a diameter which is slightly larger than thediameter of the hole 15 which extends thorugh the tubular part 8 of thering 3. The mandrel 4 must not, however, be so large as to projectbeyond the axial external surface of the side part 9, against which itmust be situated during the operation for the removal of the ring. Aswill be appreciated from FIG. 1, the ring must engage in the transitionbetween the hole 15 and the side part 9. This transition is executed asa radius 16.

The supporting part 5 of the implement is executed as a tube with anexternal periphery 18, the size of which is essentially of nosignificance, and an internal periphery 19 with a cylindrical surface.The diameter of the inner periphery 19 is such that its end edge is incontact with the radius 20 which, like the radius 16, forms thetransition between an axial surface of the ring, in this case on themain part 6, and a surface with an essentially cylindrical arrangement,in this case the external periphery of the part 6. The peripheralsurface 19 is terminated on said edge by an axial surface 21 in the part5 of the implement, and the latter must thus not extend to anysignificant degree into the axial surface of the main part 6, but mustnot be situated outside its periphery, either. The axial surface 21constitutes the bottom of a depression, the wall 22 of which constitutesa guide for the outward-bend edge of the main part 6 of theaforementioned peripheral surface which is in contact with the radius20. The ring can be centred in this way in the part 5 of the implement,so that the edge of the peripheral surface 19 engages concentricallyalong the radius 20.

The part 4 of the implement must also be arranged concentrically withthe ring. In conjunction with the use of the implement in a press, theparts 4, 5 of the implement must, in fact, be capable of being movedtowards one another with considerable force, with centring between theparts of the implement being effected with the help of centring devicesin the press. In the event of it being necessary for the removaloperation to be performed in a hand tool, this should preferably beexecuted with a draw-in bolt which extends through the centre of the twoparts of the implement and centres these in relation to one another. Inthis case the mandrel 4 must be provided with a hole for the bolt. Thesupporting part 5 for its part must be executed with a base with atranscurrent hole or with a washer to provide support for the bolt. Itis possible in this way, by threading a nut onto the bolt, for the parts4, 5 to be drawn towards one another in the manner described below.

As will have been appreciated from the foregoing, removal of the ring 3requires the ring to be laid in the depression in the supporting part 5,in which a way that the ring is centred by the peripheral surface 22.The mandrel 4 is then placed in a concentric position in relation to theinner peripheral surface 19 of the supporting part 5 and has aconsiderable downward force exerted on it. Since the ring rests with itsouter edge against the supporting part 5, whereas the mandrel 4 engageson the internal edge of the ring along a circular line inside thecircular line at the edge of the peripheral surface 19 where the ring issupported, it will be subjected along its circular, curved cross-sectionto a moment which endeavours to impart conical form to the ring in themanner illustrated in FIG. 2. The side part 9 will thus rise more andmore whilst the cylindrical part 8 begins to adopt the form of abellows.

Because of the pressure exerted against the toothed ring 11 by the sidepart 9, the toothed ring will also adopt concial form, and the teeth 12will be caused to be deflected outwards at their ends. The plastic ring13 and the canvas 1 generate little resistance and are deformed as themadrel 4 and the supporting part 5 are compressed.

As the compression continues, the angle of the conical form will becomesmaller and smaller, and the outer edge of the side part 9 and the inneredge of the toothed ring 11 will approach closer and closer to oneanother, in conjunction with which the rotating moment of the parts willincrease. As the compression continues, the side edge part 9 will slidethrough the toothed ring 11 and will then adopt cylindrical or nearenough cylindrical form; it is shown in FIG. 3 as being forced againstthe cylindrical outer surface of the mandrel 4.

Once the outer edge of the side part 9 and the inner edge of the toothedring 11 have moved past one another, the two retaining parts of thering, the main part 6 and the toothed ring 11, will have been separatedfrom one another at the same time as the retaining force between theside parts 7 and 9 will have been removed. The ring is thus no longerretained as a joint around the edge of the canvas 1, and the canvas isreleased and is able to straighten out.

As has already been mentioned, the teeth 12 will have described acurving action during the operation and are withdrawn from the plasticring 13 in this way, as well as being straightened to a certain extent.In the final phase the teeth extend largely in an axial direction andcan be withdrawn from the canvas in this way, leaving only holes withouttearing apart the canvas. No straightening operation for the teeth isrequired, as a general rule, and the ring can be removed relativelyeasily by pulling it in an axial sense if, as can be the case, if hasnot lost its grip on the canvas in conjunction with the compressingaction of the parts of the implement.

As will have been appreciated from the above, the underlying idea of theinvention is that the parts of the implement engage in a concentricmanner along the outer periphery of the ring from one side and along itsinner periphery from the other side, in such a way that a twistingaction is imparted to same. In this way the ring adopts a conical formwith a progressively smaller angle the further the parts of theimplement are forced together. The previously connected and overlappingpart is now imparted with almost cylindrical form and releases thepreviously securely pressed tooth ring. This is also imparted withconical form, which gives the teeth a tendency to extend axially, makingthem easy to release.

The invention is not entirely restricted to the type of ring illustratedand referred to by way of introduction, and the method in accordancewith the invention may conceivably also be applied to other types ofring.

The method and the implement in accordance with the invention naturallyhave the greatest significance for heavy-duty rings, which are difficultto remove, and in particular for those rings which have an inner ringsituated between outward-curved flanges. The invention can also beapplied to rings with a form other than circular, if such rings exist.The implements must be adapted in this case to suit the form of the ringin order to engage on the internal and external edges, as stated.

I claim:
 1. A method for removal of rings from a flexible material suchas canvas, a ring, which is attached to the material and to be removedfrom the same, including two annular flanges, each with an outer and aninner edge, and between portions adjacent to the inner edge of eachflange a tubular portion, the tubular portion extending through a holein the material and the flanges being pressed against opposite surfacesof the material, thereby anchoring the ring to the material; the methodincludingplacing the ring, attached to the material and intended to beremoved, on an annular support having a supporting surface extendingaround a hole and adapted to support one flange of the ring along anarrow portion at the outer edge of said one flange, the portion andinwardly being defined by an inner edge of the supporting surface;positioning an end surface of a mandrel against the other flange, theend surface of the mandrel being placed in contact with a narrow portionalong the inner edge of said other flange, the portion outwardly beingdefined by an outer edge of the mandrel, which outer edge of themandrel, along its periphery, is at a distance from said inner edge ofthe supporting surface; moving the mandrel towards the support and intothe hole of the support; performing the movement until an inner portionof the ring at its tubular portion is pressed down into the hole of thesupport and the flanges having become deformed to the shape of afrustrum of a cone; and pulling the material away with its portionadjacent to its hole out from its position between the deformed flanges.